A Synthetic Motor Control System; Possible Parallels With Transformations in Cerebellar Cortex

Abstract

In a normal person muscular activity is coordinated so as to take into account the following two factors: (1) information on the pattern of the desired movement and (2) physical constraints such as the dynamics of the moving body, limitations on its input, optimality criteria, etc. The extent of coupling between these two types of factors in producing coordinated muscle activity in the real motor system is not known. However, for the purpose of analysis and modelling one may consider a functional representation as in Fig. 1 in which the command modifier matches the desired movement signal to the dynamics of the system according to given constraints. In this paper we discuss such transformation of a step command in a mechanical system whose output may approximate fast arm movement. Possible parallels with transformations in the neural net of the cerebellar cortex are then mentioned.